Hi!
I'm not sure you know, but gtk3 flavor can use Webkit2GTK as web browser
engine, plist doesn't change, here is a diff for 26.1 port Makefile:
--- Makefile.orig Sun Jun 3 23:29:36 2018
+++ Makefile Mon Jun 4 00:13:09 2018
@@ -79,14 +79,17 @@ WANTLIB += freetype fribidi gdk-x11-2.0 gdk_pixbuf-2.0
WANTLIB += glib-2.0 gobject-2.0 gtk-x11-2.0 intl jpeg lcms2 pango-1.0
WANTLIB += pangocairo-1.0 pangoft2-1.0 png rsvg-2 tiff xcb
. elif ${FLAVOR} == "gtk3"
-CONFIGURE_ARGS+= --with-x-toolkit=gtk3
-LIB_DEPENDS+= x11/gtk+3
+CONFIGURE_ARGS+= --with-x-toolkit=gtk3 \
+ --with-xwidgets
+LIB_DEPENDS+= www/webkitgtk4 \
+ x11/gtk+3
WANTLIB += ICE MagickCore-6.Q16 MagickWand-6.Q16 SM X11 X11-xcb
-WANTLIB += Xext Xfixes Xft Xinerama Xpm Xrandr Xrender atk-1.0
-WANTLIB += cairo cairo-gobject dbus-1 fontconfig freetype fribidi
-WANTLIB += gdk-3 gdk_pixbuf-2.0 gif gio-2.0 glib-2.0 gobject-2.0
-WANTLIB += gtk-3 intl jpeg lcms2 pango-1.0 pangocairo-1.0 png
-WANTLIB += rsvg-2 tiff xcb
+WANTLIB += Xcomposite Xext Xfixes Xft Xinerama Xpm Xrandr Xrender
+WANTLIB += atk-1.0 cairo cairo-gobject dbus-1 fontconfig freetype
+WANTLIB += fribidi gdk-3 gdk_pixbuf-2.0 gif gio-2.0 glib-2.0 gobject-2.0
+WANTLIB += gtk-3 intl javascriptcoregtk-4.0 jpeg lcms2 pango-1.0
+WANTLIB += pangocairo-1.0 png rsvg-2 soup-2.4 tiff webkit2gtk-4.0
+WANTLIB += xcb
. else
ERRORS+= "Fatal: Conflicting flavor: ${FLAVOR}"
. endif
